A processor or other resource in a computer system may be capable of addressing memory and other resources directly using an address of a definite size. The maximum length of address that a resource can handle determines the extent of the address space that resource can address. A resource can access locations outside its own address space, but this typically requires indirect addressing procedures that require both time and resources. In a multi-processor system, several cells may be arranged to share a “coherency domain” of common, directly addressable address space. However, because each cell must generally be able to address the entire coherency domain directly, the total size of the coherency domain, and thus the sum of the sizes of the cells, is then limited to the address space of any one processor.